Unfortunately, the matter of choice is not yours. Once anyone reports to police a situation which might involve some kind of criminality, they will investigate and if the elements of a crime are found to exist, they will charge the person who they believe committed it. The DA's office normally does not dismiss DV cases unless for any reason it is determined that they cannot prove the charge(s) beyond a reasonable doubt at trial. Also unfortunately, charges involving domestic violence are relatively easy to prove. Your fiance needs an attorney.
The information provided in this answer is only general shall not be deemed to create an attorney-client relationship.
CO and most states do not allow alleged victims to "drop" or "press" charges and leave it to an independent and autonomous agency, the District Attorney, to determine if there is probable cause to charge someone with an assault, harassment, or other crime that is characterized as domestic violence. So, you can not get the police or the DA to drop the charges. You can express your desires to the victim/witness advocate with the DA's Office and to the judge in asking to modify the restraining order. The DA is statutorily prohibited from dismissing DV charges if there is probable cause. SO, you need to get him a good attorney. Clifton Black, David Foley, and Brian Boal are all good in the Springs.
The information provided in this answer does not create an attorney-client relationship. If you are interested in his legal services, feel free to call Chris at (303) 409-7635 at his law office in the Denver Tech Center. All initial consultations are free of charge.